Hybrid perovskite solar cell thin film configured with TiO ₂ and PTAA through RF magnetron sputtering: performance study

Abstract Fluorine-doped tin oxide (FTO) serves as a transparent conducting oxide that enables electrical conductivity, allowing the flow of electrons to external circuits. However, FTO experiences optical losses, reducing light transmission. Additionally, its improved degradation behaviour can lead to diminished functional properties. This study investigates perovskite solar cells with an FTO/Titanium dioxide (TiO 2 )/Methylammonium Lead Iodide (MAPbI 3 )/Poly-triarylamine (PTAA)/silver (Ag) structure fabricated via radio frequency (RF) magnetron sputtering, focusing on the role of TiO 2 thickness (20, 30, and 40 nm). The influence of the TiO 2 electron transport layer (ETL) thickness on the functional behaviour of Perovskite solar cells is investigated. RF magnetron sputtering technology improved interfacial bonding between the PSC and ETL, as confirmed by microstructural studies. The presence of the TiO 2 layer led to higher energy extraction and improved power conversion efficiency. However, the 40 nm TiO 2 layer exhibited superior performance and enhanced structural properties. Optical analysis revealed a 70 % reduction in transmittance and a refractive index of 2.7 at this thickness. The 40 nm TiO 2 ETL also demonstrated the lowest optical band gap (1.57 eV) and the highest absorption coefficient (1.8 × 10 5 cm −1 ), indicating improved photon absorption. Electrical characterization showed the highest conductivity (4.55 × 10 −3 S/cm) and the lowest resistivity (0.65 × 10 2 Ω cm), correlating with efficient charge transport. These improvements yielded the best photovoltaic performance, with a short-circuit current density (JSC) of 23.0 mA/cm 2 and an open-circuit voltage (VOC) of 1.08 V. This study underscores the critical role of TiO 2 thickness optimization in enhancing the efficiency of hybrid perovskite solar cells.